My iPhone won't turn on and it isn't dead. Help?

Restart the device. That's it. If issue is not resolved... Force restart iPhone - Apple Support

If iPhone still doesn’t turn on, or if it gets stuck during start up, see the Apple Support article If your iPhone, iPad, or iPod touch won’t turn on or is frozen

1. Try and Force ReStart Your iPhone as instructed in this article by Apple ➔ How to Force ReStart your iPhone. If that does not work then -
2. Follow the instructions in this article by Apple ➔ If your iPhone is Non-Responsive or Frozen and see if that helps.

Axel F.